This invention relates to rail vehicles, and more specifically to three wheel sets arranged in a bogie frame for supporting a rail vehicle.
Bogies for modern rail vehicles must often be designed to cope with high curve speeds in mostly sharp curves. An adjustable two-axle bogie, as described in CH 670 228 A5, is known for this purpose. In this two-axle bogie, the wheel sets, when negotiating curves, are in each case adjusted independently, without control input, in particular without additional adjusting devices, essentially radially to the curve to be negotiated. In this case, the wheel sets are arranged on the bogie frame via the motor by means of slanted links in such a way that a rotary movement about a vertical axis about the center of the wheel set, even with traction forces being exerted on the bogie, is possible.
Furthermore, DE 41 40 126 A1 discloses a three-axle bogie which has a radial control for the radial deflection of the wheel sets of the bogie. In this case, the wheel sets are mounted on the bogie frame in an elastic manner, the radial deflection of the wheel sets being made possible by means of steering linkages, longitudinal links, steering rods, coupling rods and bell-crank levers with arms arranged thereon.
In this three-axle bogie, the radial adjustment of the wheel sets is certainly possible, but, due to the large wheel base and as a result of permitting the radial adjustment of the wheel sets at the same time, a large number of parts, which are arranged or fitted in a complex manner, are necessary. As a result, the manufacturing costs of such a bogie increase to an intolerable extent. In addition, the maintenance of this large number of parts proves to be too costly.
Neither CH 670 228 A5 nor DE 41 40 126 A1 provides a solution for a bogie, in particular for three-axle applications required nowadays, which is cost-effective and comprehensive in terms of maintenance.
Conventional brake devices for three-axle bogies are firmly connected to the bogie frame. Such a brake device fixed to the bogie frame and acting on the respective wheel discs poses a problem with regard to its mounting on the bogie frame, since the transverse deflection and longitudinal deflection between the respective brake device and the associated wheel disc is too large in order to act on the wheel disc in an appropriate manner. Although a transversely elastic suspension of the brake device or a transverse guidance of the brake device is conceivable, it complicates the bogie construction and increases the component and maintenance costs considerably, so that a brake device fixed to the bogie frame is not suitable for a cost-effective three-axle bogie.
The object of the invention is therefore to provide an adjustable bogie with three wheel sets for a rail vehicle, which bogie permits a radial adjustment of the wheel sets, in particular even under the effect of traction force and braking force on the bogie, without control input, in particular without additional adjusting devices to be actuated, and in which the number of parts is reduced and thus an exceptionally simple construction of the bogie is possible.
This object is achieved, according to this invention by an adjustable bogie for a rail vehicle having three wheel sets. Two end wheel sets of the bogie are connected to the bogie frame at their drive devices by in each case at least one slanted link, and a center wheel set is connected to the bogie frame by at least one longitudinal link guided parallel to the longitudinal direction of the bogie frame. Due to such a coupling between the center wheel set and the bogie frame, this center wheel set can only perform a transverse movement, as a result of which conventional coupling rods are advantageously dispensed with. Furthermore, the traction and braking force can be transmitted via the center wheel set, in particular via the drive device of the center wheel set. The wheel sets of the bogie can therefore be adjusted radially in an especially simple manner.
A further design of the bogie according to the invention provides for the end wheel sets, via in each case at least one transverse link and via a drive-unit extension arm arranged in operative connection with the transverse link, to be connected to the drive unit of the center wheel set in such a way that, during a transverse movement of the center wheel set, the end wheel sets are coupled with the latter and that, during a turn-out movement of the end wheel sets, the latter are coupled in opposite directions. The radial adjustment of the wheel sets is further assisted by this design of the bogie according to the invention and can be carried out speedily.
In addition, the drive unit of each wheel set comprises at least one brake device which is arranged directly on the motor or on the gear case and acts on at least one wheel disc of the associated wheel set. As a result, a complicated mounting, which is costly and requires considerable maintenance, of the brake device on the bogie frame is dispensed with in an exceptionally advantageous manner, and the brake device may be mounted very simply directly on the drive device, in which case it follows every movement of the wheel sets.